The invention concerns a heavy-duty open-center anti-friction bearing, especially for mounting on generator sheds in wind-powered electricity-generating plants.
The anti-friction bearings employed for rotary connections in wind-powered electricity-generating plants tend to wear out relatively rapidly because their races develop grooves. The situation mainly derives from extremely small deflections adjusting for wind direction that cause the friction-reduction structures to scrape against the race. A similar situation occurs in structures that rotate on buoys, whereby the slight deflections are induced by the motion of the waves. Various means of eliminating such wear and tear by increasing the low resistance to rotation in anti-friction bearings are known. German 3 725 972 A1 for example proposes enclosing the mechanisms in an extra brake. The braking force and hence the desired resistance to rotation can be adjusted from outside. One drawback of such a design is the brake's resultant normal force, which is introduced between the rings to generate a braking moment, adding to the stress on the brake. The bearing must accordingly either be larger or shorter-lived.